Analyzing the steam demand leveling ability of the submerged nonuniformly perforated sheet in a horizontal steam generator using the STEG сode
Keywords:
horizontal steam generator, submerged perforated sheet, mathematical modelingAbstract
Simulation of thermophysical processes in the area of the submerged perforated sheet (SPS) by means of thermal-hydraulic codes still remains a difficult problem and involves the need to develop special empirical correlations based on an analysis of experimental data. In order to obtain the necessary experimental data, a so-called PGV test facility was constructed at the Electrogorsk Research Center for NPP Safety (EREC), which represents the slice-model of the PGV-1000M horizontal steam generator’s cross-section. The processes in the area of the uniformly and nonuniformly perforated SPS were investigated. An analysis of the experiments aimed at studying the SPS steam demand leveling ability carried out using the improved version of the STEG code developed at the MPEI is presented. The two-liquid model of two-phase medium is used as the basis of the mathematical model in the STEG code. It has been found from the computation studies that the simulation results are most sensitive to the closing correlations describing the interphase friction. Different interphase friction models selected from a review of available publications were implemented in the code’s mathematical model. The results of calculations carried out by means of the STEG code involving the above-mentioned interphase friction models differed significantly from the experimental results. In order to improve the agreement between the experimental and calculation results, the interphase friction models were modified. The SPS steam demand leveling ability was characterized using an integral leveling coefficient and the residual nonuniformity coefficient. An analysis of the experiments carried out at the PGV test facility aimed at investigating the SPS leveling ability that was performed using the improved version of the STEG code has revealed that the transition from uniform to nonuniform perforation of the SPS yields better integral steam demand leveling, but on the other hand, poorer steam separation is obtained due to high local values of steam velocity near the interface between the plates with different perforation degrees. Preliminary calculations of the full-scale PGV-1000M horizontal steam generator fitted with a nonuniformly perforated submerged sheet were carried out. The calculation analysis has revealed the possibility to improve the leveling effect of the SPS made with plates having different perforation degrees.
References
2. Мелихов В.И., Мелихов О.И., Парфенов Ю.В. Математическое моделирование теплогидравлических процессов в парогенераторе с помощью кода STEG //Новое в российской энергетике. 2008. № 8. С. 21—33.
3. Мелихов О.И. и др. Валидация и усовершенствование кода STEG на основе экспериментельных данных, полученных на стенде ПГВ. Расчетный анализ экспериментов на стенде ПГВ // Обеспечение безопасности АЭС с ВВЭР: Сб. трудов 9 Междунар. науч.-техн. конф. Подольск, 2015.
4. Мелихов О.И. и др. Экспериментальные исследования гидросопротивления и выравнивающей способности ПДЛ на стенде ПГВ (ЭНИЦ) // Там же.
5. Simovic Z.R., Ocokoljic S., Stefanovic V.D. Interfacial friction correlations for the two-phase flow across tube bundles // Intern. J. Multiphase Flow. 2007. V. 33. P. 217—226.
6. TRACE V5.0. Theory Manual. Field Equations, Solution methods and Physical models. U.S. Nuclear Regulation Commission. Washington, 2007.
7. TRAC PF1/MOD2: Theory Manual. Los Alamos: Los Alamos National Laboratory, 1990.
8. Блинков В.Н. и др. Влияние неравномерной перфорации погруженного дырчатого листа на выравнивание паровой нагрузки на зеркале испарения парогенератора ВВЭР // Теплоэнергетика. 2016. № 1. С. 54
9. Исламов Р.Т., Дядюра С.С., Аржаев К.А., Филиппов А.С., Артемьева М.М. Сравнение двух методов определения дефектов технических систем //Атомная энергия. 2011. Т. 110. Вып. 6. С. 303—307.
